# Lorentz contraction and Planck length and time

Given the definition of the Planck length

$$\ell_\mathrm{P} =\sqrt\frac{\hbar G}{c^3} \$$

and the Planck time

$$T_{P}\equiv \sqrt{\frac{\hbar G}{c^5}},$$

if we take into account an observer moving with respect to us with speed $v$, then due to Lorentz contraction Planck length and time would be different for different observers. How to explain this with special relativity?